Carbon products derived from lignin/carbon residue

ABSTRACT

A precursor having at least five percent of lignin based coke and d002 spacing of more than 3.36 angstroms and less 3.44 for making graphite. Methods for making a green/graphite article include mixing coke derived from a petroleum product, a coal product or a bitumen product with coke derived from lignin. Alternatively, the precursor material for the various types of coke may be mixed and coked together. The mixture may be formed into a desired shape. The article may be subsequently carbonized and graphitized. The amount of lignin derived coke comprises a sufficient quantity to change at least a selected property of the graphite article.

TECHNICAL FIELD

The disclosure relates to the field of carbon products and methods ofmaking carbon products and more specifically to the field of makinggraphite products in which lignin is a precursor for the making of thegraphite products.

Lignin, an industrial byproduct of wood-free papermaking is one of themost abundant organic based polymers on earth. Lignin is renewable,readily available and relatively inexpensive. Currently there is alimited market for lignin. In fact less than 2% of available lignin isused in the manufacturing of industrial materials or chemicals. Ligninis a polyaromatic-polyol with extensive cross linking and strong inter-and intra-molecular interactions, hence its chemical structure is verycomplex. Due to lignin's inherent high aromatic based carbon content andperceived high coking value it displays potential as a precursor forcarbon based products. However, the polyol has been found to beamorphous and highly functionalized, and attempts to utilize lignin as afeedstock for carbon products have had little success.

BRIEF DESCRIPTION

One method disclosed herein is a method of making a graphite article.Such method includes mixing a first amount of coke derived from apetroleum product, a coal product or a bitumen product with a secondamount coke derived from lignin, thereby forming a green mixture. Thegreen mixture is formed into a desired shape, thereby forming a greenarticle. The green article may be subsequently carbonized and optionallygraphitized. The second amount of coke comprises a sufficient quantityto change at least a selected property of the graphite article to obtainthe desired set of properties of the graphite article as compared to asecond graphite article made from only coke from the first amount ofcoke.

Another method disclosed herein includes a method of making a greenarticle. The method includes mixing a first amount of coke precursormaterial derived from a petroleum product, a bitumen product or a coalproduct with a second amount of coke precursor material derived fromlignin, thereby forming a precursor mixture. The precursor mixture iscoked to thereby forming a coke. The coke is formed into a desiredorientation. The second amount of coke precursor comprises a sufficientquantity to change at least one selected property of a final articleformed from the coke to obtain the desired set of properties in thefinal article as compared to a second final article made from only cokeof the first amount of coke precursor material.

A further method included herein is a method of making a green article.The method includes mixing a first amount of coke precursor materialderived from a carbon residue having a carbon content of at least 70percent with a second amount of coke precursor material derived fromlignin, thereby forming a precursor mixture. The precursor mixture iscorked thereby forming a coke. The coke is formed into a desiredorientation.

Whereby the second amount of coke precursor comprises a sufficientquantity to change selected properties of a final article formed fromthe coke to obtain the desired set of properties in the final article ascompared to a second final article made from only coke of the firstamount of coke precursor material.

A monolithic graphite article having a volume of at least 1 cc formedfrom a precursor including at least five percent by weight of ligninbased coke and d₀₀₂ spacing of more than 3.36 angstroms and less 3.44.

It is to be understood that both the foregoing general description andthe following detailed description provide embodiments of the disclosureand are intended to provide an overview or framework of understandingthe nature and character of the invention as it is claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a TGA of decant oil sample used in the example.

FIG. 2 is a TGA of a HWL sample used in the example

FIG. 3 is a TGA of lignin samples, decant oil sample and variousmixtures of the two

FIG. 4 is plot of the CTE of a graphite rod vs. percentage of SWKL usedas a precursor for the graphite rod.

FIG. 5 is plot of the CTE of a graphite rod vs. percentage of HWL usedas a precursor for the graphite rod.

FIG. 6 is plot of the CTE of a graphite rod vs. percentage of HWL usedas a precursor for the graphite rod, HWL and decant oil coked separately

FIG. 7 is a XRD for calcined HWL decant oil mixtures.

FIG. 8 is a XRD for calcined SWKL decant oil mixtures.

FIG. 9 is a plot of XRD peak intensity vs. CTE for HWL decant oilmixtures of calcined cokes.

FIG. 10 is a XRD for HWL decant oil coke rods.

FIG. 11 is a plot of XRD peak intensity vs. CTE for HWL decant oilmixtures of coke rods.

DETAILED DESCRIPTION

The concepts disclosed herein relate to the use of lignin as a precursorfor carbon products.

Typical sources of lignin include Weyerhaeuser Co. of Washington State;Lignol Innovations of British Columbia, Canada; Mascoma of Lebanon,N.H.; Virdia of Redwood City, Calif.; and Fibria Cellulose of Sao Paulo,Brazil.

Lignins can be grouped into three (3) broad classes: softwood (“SWKL”)or coniferous (gymnosperm), hardwood (“HWL”) (dicotyledonousangiosperm), and grass or annual plant (monocotyledonous angiosperm)lignins and combinations thereof. Lignin may also be prepared from othertypes of biomass, including grasses, and consistent batches oflignin-rich materials recovered from the waste materials in large-scalebrewing or biorefinery processes. An example of the lignin precursorincludes softwood alkali lignin which may be obtained from the blackliquor from softwood alkali pulping processes. In the manufacture ofwood pulp, some of the lignin and hemicelluloses are solubilized andseparated from the cellulose. The black liquor from the pulping processis the solubilized lignin and hemicellulose.

Hardwood feedstocks include Acacia; Afzelia: Synsepahim duloificum;Albizia; Alder (e.g. Alnus gltuinosa, Almus rubra); Applewood; Arbutus;Ash (e.g. F. nigra, F. quadrangulata, F. excelsior, F. pennsylvanicalanceolata. F. Latifolia, F. profunda, F. americana); Aspen (e.g. P.grandidentata, P. tremula, P. tremuloides); Australia Red Cedar (Toonaciliata); Ayna (Distemonanthus benthamianus); Balsa (Ochromapyramidale); Basswood (e.g. T. americana, T. heterophylla); Beech (e.g.F. sylvatica, F. grandifolia); Birch; (e.g. Betula populifolia, B.nigra, B. papyrifera, B. lenta, B. alleghaniensis/B. lutea, B. pendula,B. pubescens); Blackbean; Blackwood; Bocote; Boxelder: Boxwood;Brazilwood; Bubinga; Buckeye (e.g. Aesculus hippocastanum Aesculusglabra, Aesculus flava/Aesculus octandra); Butternut; Catalpa; Cherry(e.g. Prunnus serotina, Prunus pennsylvanica, Prunus avium); Crabwood;Chestnut; Coachwood; Cocobolo; Corkwood; Cottonwood (e.g. Populusbalsamifera, Populus deltoides, Populus sargentii, Populusheterophylla); Cucumbertree; Dogwood (e.g. Cornus florida, Cornusnutallii) Ebony (e.g. Diospyros kurzii, Diospyros Melanida, Diospyroscrassiflora); Elm (e.g. Ulmus americana, Ulmus procera, Ulmus thomasii,Ulmus rubra, Ulmus glabra); Eucalyptus; greenheart; Grenadilla; Gum(e.g. Nyssa sylvatica, Eucalyptus globulus, Liquidambar styraciflua,Nyssa aquatica); Hickory (e.g. Carya alba, Carya glabra, Carya ovata,Carya laciniosa); Hornbeam, Hophornbeam; Ipe; Iroko; Ironwood (e.g.Bangkirai, Carpinus caroliniana, Casuarina equisetifolia, Chrocbangarpiasubargentea, Copaifera spp., Eusideroxylon zwageri, Guajacum officinale,Guajacum sanctum Hopea odorata, Ipe, Krugiodendron ferreum Lyonothamnuslyonii (L. floribundus), Mesua ferrea Olea spp., Olneya tesota, Ostryavirginiania, Parrotia persica, Tabebuia serratifolia); Jacaranda;Jotoba; Lacewood; Laurel; Limba; Lignum vitae; Locust (e.g. Robiniapseudacacia, Gleditsia triancanthos); Mahogany; Maple (e.g. Acersaccharum acer nigrum, Acer negundo, Acer rubrum, Acer saccharinum, Acerpseudoplatanus); Meranti; Mpingo; Oak (e.g. Quercus macrocarpa, Quercusalba, Quercus stellata, Quercus bicolor, Quercus virginiana, Quercusmichauxii, Quercus prinus, Quercus mublenbergii, Quercus chrysolepis,Quercus lyrata, Quercus robur, Quercus petraea, Quercus rubra, Quercusvelutina, Quercus laurifolia, Quercus falcata, Quercus nigra, Quercusphellos, Quercus texana); Obeche; Okoume; Oregon Myrtle; California BayLaurel; Pear; Poplar (e.g. P. balsamifera, P. nigra), Hybrid Poplar(Populus x Canadensis); Ramin; Red cedar; Rosewood.; Sal; Sandalwood,Sassafras; Satinwood; Silky Oak; Silver Wattle; Snakewood; Sourwood;Spanish cedar; American sycamore; Teak; Walnut (e.g. Juglans nigra,Juglans regia); Willow (e.g. Salix nigra, Salix alba); Yellow poplar(Liriodendron tulipifera); Bamboo; Palmwood; and combinations/hybridsthereof.

For example, hardwood feedstocks may be selected from acacia, aspenbeech, eucalyptus, maple, birch, gum, oak, poplar, andcombinations/hybrids thereof, preferably from Populus spp. (e.g. Populatremuloides), Eucalyptus asp. (e.g. Eucalyptus globulus), Acacia spp.(e.g. Acacia dealbata), and combinations/hybrids thereof.

Softwood feedstocks include Araucaria (e.g. A. cunninghamii, A.augustifolia, A. araucana); softwood Cedar (e.g. Juniperus virginiana,Thuja plicata, Thuja occidentalis, Chamaecyparis thyoides, Callitropsisnootkatensis); Cypress (e.g. Chamaecyparis, Cupressus Taxodium,Cupressus arizonica, Taxoditum distichum, Chamaecyparis obtusa,Chamaecyparis lawsoniana, Cypressus semperviren); Rocky Mountain Douglasfir; European Yew; Fir (e.g. Abies Balsamea, Abies alba, Abies procera,Abies amabilis); Hemlock (e.g. Tsuga camadensis, Tsuga mertensiana,Tsuga heterophylla); Kauri; Kaya; Larch (e.g. Larix decidua, Larixkaempferi, Larix laricina, Larex occidentalis) Pine (e,g. Pinus nigra,Pinta banksiana, Pinus contoria, Pinus radiata Pinus ponderosa, Pinusresinosa, Pinus sylvestris, Pinus sirobus, Pinus monticola, Pinuslambertiana, Pinus taeda, Pinus palustris, Pinus rigida, Pinus echinata)Redwood; Rimu; Spruce (e.g. Picea abies, Picea mariana Picea rubens,Picea sitchensis, Picea glauca); Sugi; and combinations/hybrids thereof.

For example, softwood feedstocks which may be used herein include cedar;fir; pine; spruce; and combinations thereof. The softwood feedstocks maybe selected from loblolly pine (Pinus taeda) radiata pine, jack pine,spruce (e.g. white, interior, black), Douglas fir, Pinus silvestris,Picea abies, and combinations/hybrids thereof. Further, the softwoodfeedstocks may be selected from pine (e.g. Pinus radiata, Pinus taeda);spruce; and combinations/hybrids thereof.

Other sources of graphite precursors include a petroleum product, a coalproduct or bitumen product. The petroleum product may include at leastone of decant oil (“DO”), decant oil based pitch, petroleum pitch andcombinations thereof. The coal product may include at least one of coaltar, coal tar pitches, coal tar distillate and combinations thereof. Thebitumen product may include at least one of mineral wax, shale oil, oilsands and combinations thereof. Any one of the afore noted graphiteprecursors can be used in any combination thereof.

In a further embodiment the graphite precursor may be carbon residue.The carbon residue has a carbon content of at least seventy (70%)percent. Preferably more than seventy-five (75%) percent carbon. Thecarbon content of a material may be measured by CHN analysis. A CHNAnalyzer is a scientific instrument which can determine the elementalcomposition of a sample. One example of a CHN analyzer is a 2400 CHN/OAnalyzer or 2400 CHN/O Analyzer II, both available from Perkin Elmer ofWaltham, Mass. U.S.A.

In a particular embodiment, the carbon residue may be selected from thegroup of coal based raw material(s), petroleum based raw material(s) andcombinations thereof. The mixture may form a carbon product precursormixture. Examples of carbon residue include petroleum based productssuch as decant oil, decant oil based pitch and petroleum pitch as wellas coal based products such as, coal tar, coal tar distillate, coal tarpitches, mesophase pitch, isotropic pitch, and combinations thereof ofany of the afore petroleum and coal based products. Another example of anon-exhaustive list of carbon residues include decant oil, decant oilbased pitches, coal tar pitches, petroleum pitches, coal tar distillatesand combinations thereof. The above examples and descriptions of acarbon residue are applicable to all embodiments disclosed herein.

An embodiment disclosed herein includes a method of making a graphitearticle with a desired set of properties. The method includes mixing afirst amount of coke derived from a petroleum product, a coal product orbitumen product with a second amount of coke derived from lignin,thereby forming a green mixture. The green mixture is formed into adesired shape, thereby forming a green article. Examples of the formingmay include extrusion, milling, molding, hot pressing, isostaticpressing, and cold pressing. Prior to forming if so desired, eitheramount of coke or both coke may be milled or sized as desired.

The green article may be carbonized and, if desired, subsequentlygraphitized. The carbonization and graphitization steps may incurconsecutively in time within the same processing equipment or remotelyin different processing equipment as well as at different locations. Agreen article is an article which includes raw materials which have notbeen subjected to a carbonization step. Such as the binder pitch or animpregnation pitch included in an article after forming or impregnationbut prior to carbonization of the article.

Preferably the second amount of coke derived from lignin comprises asufficient quantity to change selected properties of the graphitearticle to obtain the desired set of properties in the graphite articleas compared to a second graphite article made from only coke from thefirst amount of coke derived from the petroleum product, the a coalproduct or the bitumen product. Examples of desired properties that maybe adjusted by the use of the second amount of coke include thecoefficient of thermal expansion (“CTE”), the d₀₀₂ spacing between thelayered planes within the graphite article, the char weight or modifiedConradson Carbon (“MCC”) of the article, coke yield, bulk density,specific resistance, and real density.

The first amount of coke and the second amount of coke may be calcinedeither together or separately, additionally the first amount of coke andthe second amount of coke may be calcined under the same conditions orunder separate conditions. Typical calcining conditions include heatingthe coke to a temperature of about 800-1600° C., usually about1100-1400° C. The calcining usually takes place in a rotating drum atatmospheric pressure.

An exemplary embodiment of the coking process may include mixing ligninand decant oil. The mixture may be prepared by first heating the decantoil to slightly above 60° C. and then mixed with the solid lignin viamechanical stirring while heating at 60° C. for 10 minutes or until thelignin appeared evenly distributed in the decant oil.

Coking of the lignin, decant oil, or mixtures thereof may be carried outin a vessel without agitation. Samples to be coked may be carbonized ina reactor at a temperature of at least 400° C., more preferably at leastabout 450° C. under pressure in an inert environment. The reactor may beheated at a rate of about 100° C. per hour until desired carbonizationtemperature is reached. The temperature of the reactor is held for adesired period to allow carbonization to occur. The reactor is thenallowed to cool below 50° C. prior to removal of the coke. The cokeremoved from the reactor may be referred to as “green” coke. Thisprocess can be used for a feedstock of just lignin, just carbon residue(e.g., decant oil), or a mixture of both

The green coke may be crushed and calcined at temperatures in the rangeof 1100 to 1600° C. for a desired period of time, thereby formingcalcined coke.

In another example of a coking process, a heavy hydrocarbon feedstock isthermally decomposed, or cracked, into coke and lighter hydrocarbonproducts. Of the various types of coking processes currently used thedelayed coking has emerged as the technology of choice by most refinersdue to its lower investment costs and its ability to produce comparableyields of products but of higher quality. A typical delayed cokingprocess is a semi-continuous process in which heavy hydrocarbonfeedstock is heated to cracking temperature using a heat source such asa coker furnace. The heated feedstock is then fed continuously to acoking drum, where it reacts in its contained heat to convert thefeedstock to coke and cracked vapors. The cracked vapors are passedoverhead to a coker fractionator, condensed and recovered as lowerboiling hydrocarbon products. The fractionator bottoms may be recycledto the feedstock if desired. When the coke drum contents reach apredetermined level, the feedstock supply is switched to another drum,and the full drum is cooled and de-coked. The entire process for onedrum, from fill cycle start to fill cycle start, may require between 18and 120 hours.

In a delayed coking process, feedstock is introduced to the coking drumduring the entire fill cycle. If the fill cycle lasts for 30 hours, thefeedstock first introduced to the coking drum is subjected to cokingconditions for that 30 hour period of time. Each succeeding increment offeedstock, however, is coked for a lesser period of time and the finalportion of feedstock introduced to the coking drum is subjected tocoking conditions only for a relatively short period of time. Forfurther guidance on the delayed coking process, see U.S. Pat. No.7,371,317 which is incorporated herein by reference in its entirety.

As, for the graphite article it may be formed with at least about 0.01percent by weight of the second amount of coke derived by lignin to nomore than about seventy-five (75%) percent by weight such second amountof coke. In a further embodiment, the weight percentage of the secondamount of coke used to make the graphite article may include 0.1 percentup to about sixty (60%) percent. In another further embodiment, theweight percentage of the second amount of coke may comprise about one(1%) percent up to about fifty (50%) percent.

Another method disclosed herein includes a method of making a greenarticle. The green article is an article that has not been subjected toeither carbonization or graphitization conditions. For carbonization totake place, typically the article has been heated to at least 400° C.The method includes mixing a first amount of coke precursor materialderived from a petroleum product, bitumen product or a coal product witha second amount of coke precursor material derived from lignin, therebyforming a precursor mixture. The petroleum product, the bitumen productor the coal product in this embodiment are the same as described above.

This method further includes coking the precursor mixture therebyforming coke and forming the coke into a desired orientation. As part ofthe forming, the coke may be mixed with other materials such as a bindersuch as pitch or any other suitable binder material as well as additivessuch as carbon fibers or graphite powders. The applicable formingtechniques include all of the forming techniques listed above. If sodesired prior to forming the coke as well as any other desired materialto be added to the coke may be milled and sized to a desiredspecification.

Preferably, the second amount of coke precursor derived from lignincomprises a sufficient quantity to change at least a selected propertyof a final article formed from the coke to obtain the desired set ofproperties in the final article as compared to a second final articlemade from only coke of the first amount of coke precursor materialderived from the petroleum. product, the coal product or the bitumenproduct.

As for the final article it may be formed with at least about 0.01percent by weight of the second amount of coke derived by lignin to nomore than about seventy-five (75%) percent by weight such second amountof coke. In a further embodiment, the weight percentage of the secondamount of coke used to make the final article may include 0.1 percent upto about sixty (60%) percent. In another further embodiment, the weightpercentage of the second amount of coke comprises about one (1%) percentup to about fifty (50%) percent. This paragraph also applies to themaking of the green article with a carbon residue as described below.

A further method of making a green article includes mixing a firstamount of coke precursor material derived from a carbon residue having acarbon content of at least seventy (70%) percent with a second amount ofcoke precursor material derived from lignin, thereby forming a precursormixture. The precursor mixture is then coked and the resultant coke isformed into a desired orientation. Preferably, the second amount of cokeprecursor derived from lignin comprises a sufficient quantity to changeat least a selected property of the final article formed from the coketo obtain the desired set of properties in the final article as comparedto a second final article made from only coke of the first amount ofcoke precursor material from a the carbon residue. CHN analysis may beused to determine if the carbon residue has the aforementioned carboncontent.

Also included in this disclosure is a monolithic graphite article havinga volume of at least 1 cubic-centimeter (“cc”) formed from precursorsincluding at least five (5%) percent by weight of lignin based coke andd₀₀₂ spacing of more than 3.36 angstroms and less 3.44. In a particularembodiment, the article exhibited a 2θ angle between 26° and 27°. In afurther embodiment, the graphite article may have a CTE of at least 1.59ppm/° C. further a CTE of at least 2.14 pm/° C., and even further a CTEof at least 4.5 ppm/° C. The above CTE's are measured in the with graindirection between the temperatures of 30-100° C.

The above particular embodiments are not mutually exclusive of eachother.

The various embodiments described herein can be practiced in anycombination thereof. The above description is intended to enable theperson skilled in the art to practice the invention. It is not intendedto detail all of the possible variations and modifications that willbecome apparent to the skilled worker upon reading the description. Itis intended, however, that all such modifications and variations beincluded within the scope of the invention that is defined by thefollowing claims. The claims are intended to cover the indicatedelements and steps in any arrangement or sequence that is effective tomeet the objectives intended for the invention, unless the contextspecifically indicates the contrary.

EXAMPLES

The embodiments disclosed herein will now be further described by thebelow non-limiting examples.

Two (2) types of lignin were used in the following examples. A hardwoodlignin (“HWL”) obtained from Mascoma, a biomass to ethanol refinerylocated in Michigan. Softwood Kraft lignin (“SWKL”) was obtained fromWeyerhaeuser. The dried Mascoma hardwood lignin was used as received,however the Weyerhaeuser lignin was obtained as “lignin cake” andcontained 45% water by weight. The lignin cake was dried at 105° C.under vacuum for several hours until no weight loss was observed uponfurther heating. CHN analysis of the lignin raw materials is provided inTable 1. Mott filtered decant oil was used as received from SeadriftCoke, LLP. Koppers 111° C. softening point coal tar pitch was used asthe binder in preparation of the coke rods. Commercially available SRSoil was used as received.

TABLE 1 CHN Analysis of Raw Lignin Lignin Carbon % Hydrogen % Nitrogen %Mascoma HWL 59.26 5.5 0.5 Wayerhauser SWKL 54.14 4.33 0.80

X-Ray diffraction data was collected on a Rigaku Ultima 3 ditfractometerequipped with a ¼° divergence slit, a 0.30 mm receiving slit, a graphitemonochrometer and a scintillation detector. The X-Ray source (Cukα₁λ1.54056 Å) was used at 40 kV and 44 mA. Diffraction was undertakenfrom 5-90° 2θ with a step size of 0.02° 2θ and a dwell time 3 sec/stepat room temperature. The original patterns were analyzed using jade 9+software (Materials Data Inc., 2011). Profile fitting using Pearson-VIIfunction was applied to find the peak value and the full-widthhalf-maximum (FWHM).

Thermo gravimetric analysis (TGA) was completed using a Q5000 modulatedTGA with a platinum pan under N₂ atmosphere with a heating rate of 5° C.per min from room temperature to 1.000° C. CTE measurements were carriedout at 100° C.

Lignin/decant oil mixtures were prepared by first heating the decant oilto slightly above 60° C. and then mixing it with the solid lignin viamechanical stirring while heating at 60° C. for 10 minutes or until thelignin was evenly distributed in oil.

Pyrolysis of lignin, decant oil, and mixtures thereof were carried outin a 4 liter pressure vessel without stirring. Typically a 2 L closedcontainer was charged with 1000 g of feedstock and placed inside thepressure vessel prior to pyrolysis. All samples were pyrolized at 475°C. for 16 hours under 200 psi of N2. The vessel was heated at a rate of100° C. per hour to 450° C. and then at a rate to of 10° C. hour untilthe hold temperature of 475° C. was reached. The reactor was thenallowed to cool below 50° C. prior to removal of the container.

The analysis and comparison of coke quality was performed on green coke,calcined coke and graphitized coke rods composed of various weightpercentages of both lignin and decant oil. The green coke was crushedand calcined at 1420° C. for 30 minutes. Graphite rods were firstprepared by milling 400 g of calcined coke. Then 300 grams of 55 flour(55% of such flour will pass through a 200 mesh semen) was mixed with106 g of binder pitch and 12 g of SRS oil. The rods were then extrudedfrom this mixture and baked at 1000° C. for 2 hours with a ramp rate of60° C./minute. The rods were then graphitized at 3000° C. for 30 minuteswith a ramp rate of 1000° C./hour.

TGA Analysis

FIG. 1 and FIG. 2 show TO curves of decant oil and HWL respectively. Theinherent differences in reactivity under the same pyrolysis conditionsare apparent from these two curves. Gradual heating of decant oil to1000° C. produces a char yield of 2.1% (FIG. 1) as compared to 35.1% forHWL (FIG. 2) and 40.0% for SWKL (FIG. 3, curve 6). During coking decantoil undergoes cracking and polymerization.

Lignin does not undergo evaporation, rather it decomposes into lighterfragments. Its higher reactivity due to phenolic hydroxyl groups allowsfor facile radical-induced condensation of aromatic nuclei. Thus, higherchar yields are obtained from the lignin samples as compared to thedecant oil sample.

In order to investigate the interaction between lignin and decant oil,several mixtures of HWL and decant oil were prepared and analyzed by TGA(FIG. 3). FIG. 3 shows a clear trend between lignin percentage and charyield. In FIG. 3, DO is line 1; Mascoma lignin (HWL) is line 2; line 3is a 50% mixture of DO and HWL by weight; line 4 is a mixture of 33% HWLand 67% DO by weight; line 5 is a mixture of 25% HWL and 75% DO byweight, line 6 is SWKL. It was assumed that if no interactions betweenthe two components occurred then pyrolysis of the mixtures would yield achar weight equal to the sum of individual components. However this wasnot the case as shown in Table 2.

TABLE 2 TGA: Char yield of Lignin/Decant Oil Mixtures Decant 50% 33% 25%oil HWL Lignin Lignin Lignin Expected NA NA 18.50 12.87 10.25Experimental 2.06 35.07 24.52 16.96 14.28 Weight % NA NA 32.54 31.7839.32 Increase

According to the individual pyrolysis experiments of decant oil and HWLfrom Mascoma it was expected that a 50/50 mixture would yield 18.5% aschar however 24.5% was obtained experimentally. In fact all mixtures ledto an average 34.6% increase in char yield. The results indicate thatthe mixtures did not follow the rule of mixtures. Due to theinsolubility of lignin in petroleum residues the lignin was expected tohave a negative impact on the morphology and physical characteristics ofthe coke obtained from the decant oil portion of the mixture. In otherwords, the resulting coke produced from a mixture of lignin and decantoil would be a mixture of bio-coke and sponge coke or lower qualitygrade petroleum coke. This was not the case.

Coking Experiments

Various mixtures of HWL, SWKL and decant oil were prepared and cokedunder conditions often used for the preparation of needle coke fromdecant oil. All coking experiments composing mixtures or individual rawmaterials were executed at 475° C. with a hold time of 16 hours with aheating rate of 100° C./hour under 200 psi of N₂. The corresponding cokeyields were summarized in Table 3.

TABLE 3 Product Yields of Pyrolysis/Coking Experiments SWKL Decant OilLignin % 100 50 33 25 20 10 5 0 Coke Yield % 52.50 55.49 54.76 51.2055.90 54.28 56.30 55.60 Volitile % 47.50 44.51 45.24 48.80 44.10 45.7243.70 44.40 Theoretical yield NA 54.05 54.58 54.83 54.98 55.29 55.45 NAHWL Decant Oil Lignin % 100 50 33 25 20 10 5 0 Coke Yield % 52.98 49.5149.53 54.25 49.77 49.77 47.83 55.60 Volitile % 47.02 50.49 50.47 45.7550.23 497.67 956.60 44.40 Theoretical yield NA 54.29 54.74 54.95 55.0855.34 55.47 NA

The reported yields are an average of two (2) runs executed for eachmixture. Expected/Theoretical yields were calculated based on yieldsobtained from individual SWKL, HWL, and decant oil coking runs whileassuming no molecular interaction between the individual components ofthe mixture. The theoretical and experimental yields are relativelyclose in comparison with the theoretical yields being slightly higher.The relatively high coke yields of lignin led to product yields verysimilar to that of pure decant oil.

Product Analysis

The characteristics and physical properties of carbon products can bedirectly related to the raw materials used, their composition and thewhether the materials are mixed before coking or after coking. Commonmeasures of these properties are the coefficient of thermal expansion(CTE), electrical resistance, and density. For example, the desiredproperties of regular graphite electrodes and those used in ultra-highpower furnaces are provided below in Table 4. CTE data provided hereinis in the with-grain direction.

TABLE 4 Properties of Graphite Electrodes Property Regular Electrode UHPCTE(10^(6/)° C.) 0.7-2.7 0.3-10  Bulk Density g/cc 1.55-1.70 1.60-1.75Specific Resistance (μΩm)  6.0-10.0 4.0-7.0

In order to compare the properties of the SWKL/DO and HWL/DO cokes wereprepared; each mixture was calcined, blended with pitch, extruded into5.0 inch graphite rods with a diameter, of 19 mm, baked and graphitized.Each graphite rod was then analyzed, the summaries of which are providedin Table 5 and Table 6.

Under the aforementioned coking, conditions, the pure decant oil roddisplayed a value of 0.266 ppm/° C. between the temperatures of 30-100°C. It is clear from Tables 5 and 6 that CTE increases with increasedlignin percentage. Interestingly, on average, mixtures of HWL providedCTE values higher than those of SWKL. This was unexpected because SWKLcontains more hydroxyl functionalities than HWL, which renders it morereactive and it was expected to form coke with less ordered graphiticstructures. It was found that up to 20 weight percent SWKL may beincorporated while holding CTE values below 1.0 ppm/° C. Correlations oflignin percentage and CTE are provided in FIGS. 4 and 5. The percentagesin Tables 5 and 6 are by weight.

TABLE 5 Properties of Co-Coked SWKL/DO Rods Specific Bulk Real LigninCTE Resistance Density Density Blend % (ppm/° C.) (μΩm) g/cc g/cc DO 00.238 9.77 1.46 2.211 SWKL/DO 50 5.856 18.18 1.52 2.01 SWKL/DO 33 2.63910.57 1.57 2.091 SWKL/DO 25 1.415 10.76 1.54 1.903 SWKL/DO 20 0.67810.12 1.50 2.14 SWKL/DO 10 0.390 9.02 1.48 2.15 SWKL/DO 5 0.266 9.4 1.452.151

TABLE 6 Properties of Co-Coked HWL/DO Rods Specific Bulk Real Lignin CTEResistance Density Density Blend % (ppm/° C.) (μΩm) g/cc g/cc DO 0 0.2389.77 1.46 2.211 HWL/DO 50 4.692 26.04 1.50 1.989 HWL/DO 33 4.668 13.531.60 2.111 HWL/DO 25 2.192 10.22 1.58 2.143 HWL/DO 20 1.596 11.06 1.502.125 HWL/DO 10 0.665 10.52 1.47 2.147 HWL/DO 5 0.339 10.27 1.44 2.141

The hypothesis that lignin disturbs the coalescence of mesophase intolarge domains of highly ordered graphic structures and results in spongecoke was tested by preparing/pyrolyzing lignin coke and decant oil basedcoke separately. Each batch was also calcined separately underconditions identical to those for the co-pyrolized samples. Calcinedcoke flour was then milled and mixed in the desired ratio prior to thepreparation of the corresponding coke rod. The coke rods prepared werebaked and graphitized under identical procedures mentioned previously.

TABLE 7 Properties of Separately Pyrolized HWL/DO Coke Rods SpecificBulk Lignin CTE Resistance Density Blend % (ppm/° C.) (μΩm) g/cc DO 00.238 9.77 1.46 HWL/DO 50 1.55 29.25 1.24 HWL/DO 25 0.93 14.96 1.39HWL/DO 20 0.77 12.76 1.43 HWL/DO 10 0.46 10.34 1.46 HWL/DO 5 0.336 9.781.46

It is clear from Table 7 and FIG. 6 that notably lower CTE values may beobtained from preparing graphite electrodes with mixed lignin/DO cokesrather than co-cokes. Although at concentrations below 10% co-cokeproduced rods exhibited slightly higher CTE. Interestingly however, theeffect on specific resistance remains relatively unchanged while “bulkdensity” decreases slightly. Employing this method of preparation allowsfor the incorporation of 25% lignin while holding CTE to below 1 ppm/°C. For other specialty products requiring higher CTE values and higherdensity, co-pyrolysis is a more suitable method of coke preparation.

TABLE A FOR FIG. 7 percentages by weight (1) 90% DO 10% HWL (2) 95% DO5% HWL (3) 80% DO 20% HWL (4) 67% DO 33% HWL (5) 50% DO 50% HWL (6) 25%DO 75% HWL (7) 33% DO 67% HWL (8)  0% DO 100% HWL

Though not to be limited to any particular theory it is believed thatthe change in the properties of graphite artifacts with increasinglignin percentage is attributed to the formation of less orderedturbostratic carbon structures. An examination of the calcined andgraphitized samples by XRD provided insight into this phenomenon. It wasobserved that increasing lignin percentage leads to a pronouncedincrease in the (d₀₀₂) diffraction peak in both the calcined andgraphitized mixtures. XRD analysis of the calcined HWL and SWKL areshown in FIGS. 7 and 8 respectively. All percentages are by weight.

TABLE B FOR FIG. 8 percentages by weight (1) 90% DO 10% SWKL (2) 95% DO 5% SWKL (3) 80% DO 20% SWKL (4) 75% DO 25% SWKL (5) 67% DO 33% SWKL (6)50% DO 50% SWKL

While two distinct peaks corresponding to graphitic and turbostraticcarbons are not present, it is assumed the peaks shown are a product ofthe coalescence of the individual peaks. This results in a broadening ofthe peak with increased lignin percentage. The 2θ values of the mixturesapproach the value of 26.54° reported for the (d₀₀₂) peak of graphitewith an average d₀₀₂ of 3.46 Å. XRD analysis of calcined lignin, cokescontaining lignin percentages greater than 50% display peak heights ofnegligible value (FIG. 7). Interestingly the mixture containing 10%lignin displays a peak intensity greater than the 5% lignin mixture(FIG. 7). The same phenomenon is observed for the SWKL calcined mixturesas well (FIG. 8).

FIG. 9 shows a correlation between the (d₀₀₂) peak intensity and thecorresponding CTE values. It is expected that at concentrations higherthan 50% HWL CTE values will approach a threshold, whereby CTE no longerincreases with increased lignin percentage.

XRD analysis of the graphitized rods is summarized in Table 8 and shownin FIG. 10 for the coke rods. The values obtained for 2θ and d₀₀₂approach that of the theoretical values for graphite.

TABLE C FOR FIG. 10 percentages by weight (1) 95% DO  5% HWL/DO (2) 90%DO 10% HWL/DO (3) 80% DO 20% HWL/DO (4) 75% DO 25% HWL/DO (5) 67% DO 33%HWL/DO (6) 50% DO 50% Lignin

TABLE 8 XRD analysis of HWL/DO graphitized rods % Peak CTE Lignin Height(ppm/° C.) 2Θ d₀₀₂(Å) 50 7777 4.692 26.417 3.431 33 17581 4.668 26.3683.373 25 51109 2.192 26.439 3.369 20 73372 1.596 26.403 3.373 10 1034130.665 26.419 3.371 5 112669 0.238 26.422 3.371

Similar to the calcined cokes there was an obvious correlation betweenpeak height and CTE in the graphitized rods, (FIG. 11 and Table 8).Mixtures containing greater than 25% lignin display a negligible peakheight which is characteristic of an amorphous structural ordering andcrystalinity of such cokes which exhibit extremely high electricalresistivity and CTE values.

It should be noted that the discrepancy in FIG. 7 whereby the mixturecontaining 10% lignin displayed a 2θ peak intensity greater than themixture containing 5% lignin does not repeat in the XRD analysis of thegraphitized rods (FIG. 10).

Mixtures containing various weight percentages of HWL, SWKL and decantoil were prepared and pyrolized under conditions designed for thepreparation of high quality petroleum coke. The effects of ligninpercentage on yield, CTE, specific resistivity, and density wereexamined. XRD analysis showed clear correlations between d₀₀₂ peakintensity, and CTE in both calcined cokes as well as graphite rods. Itwas also shown that much lower CTE values are obtained from coke rodsprepared from individually pyrolized mixtures of lignin and DO ascompared to co-coked mixtures. It was found that at least up to twenty(20%) weight percent SWKL may be incorporated into mixtures with DOwhile holding CTE values below 1.0 ppm/° C. employing co-coked and atleast twenty-five (25%) weight percent employing pre-pyrolized lignin/DOmixtures.

The above description is intended to enable the person skilled in theart to practice the invention. It is not intended to detail all thepossible variations and modifications that will become apparent to theskilled worker upon reading the description. It is intended, however,that all such modifications and variations be included within the scopeof the invention that is defined by the following claims.

Thus, although there have been described particular embodiments of thepresent invention of a new and useful method for making carbon fiber, itis not intended that such references be construed as limitations uponthe scope of this invention except as set forth in the following claims.

What is claimed is:
 1. A method of making a green article comprising: a.mixing a first amount of coke precursor material derived from apetroleum product with a second amount of coke precursor materialderived from lignin, thereby forming a precursor mixture; b. coking theprecursor mixture thereby forming coke; and c. forming the coke into adesired orientation whereby the second amount of coke precursorcomprises a sufficient quantity to change at least one selected propertyof a final article formed to obtain the desired set of properties in thefinal article as compared to a second final article made from the cokeprecursor material derived from the petroleum product.
 2. The method ofthe claim 1 wherein the second amount of coke precursor material derivedfrom lignin comprises by weight at least 0.01 percent to less than 50percent of a total amount precursor material used to make the coke. 3.The method of claim 1 wherein the first amount of coke precursormaterial derived from the petroleum product comprises at least one ofdecant oil, decant oil based pitch, petroleum pitch and combinationsthereof.
 4. The method of claim 1 wherein the petroleum productcomprises decant oil and the first amount of coke comprises needle coke.5. The method of claim 1 wherein the selected property includes thecoefficient of thermal expansion (CTE).
 6. The method of claim 1 whereinthe selected property includes the d₀₀₂ spacing between layered planeswithin the graphite article.
 7. The method of claim 1 wherein theselected property includes the char weight of the graphite article. 8.The method of claim 1 wherein the selected property includes themodified Conradson carbon (MCC) of the graphite article.
 9. The methodof claim 1 wherein the selected property includes coke yield.
 10. Themethod of claim 1 wherein the selected property includes at least one ofbulk density of the graphite article, specific resistance of thegraphite article and real density of the graphite article.
 11. Agraphite article made by the method of claim 1, wherein the graphitearticle has a volume of at least 1 cubic centimeter formed from aprecursor including at least five percent by weight of lignin based cokeand the graphite article has d₀₀₂ spacing of more than 3.36 angstromsand less 3.44.
 12. A graphite article made by the method of claim 1,wherein the graphite article exhibits a 2θ angle between 26° and 2.7°.13. A graphite article made by e method of claim 1, wherein the graphitearticle has a CTE of at least 0.26 ppm/° C.
 14. The graphite of claim13, wherein the graphite article has a CTE of at least 1.59 ppm/° C. 15.A method of making a green article comprising: a. mixing a first amountof coke precursor material derived from a carbon residue having a carboncontent of at least 70 percent with a second amount of coke precursormaterial derived from lignin, thereby forming a precursor mixture; b.coking the precursor mixture thereby forming coke; and c. forming thecoke into a desired orientation, whereby the second amount of cokeprecursor comprises a sufficient quantity to change selected propertiesof a final article formed to obtain the desired set of properties in thefinal article as compared to a second final article made from the cokeprecursor material having the carbon content of at least 70 percent. 16.The method of claim 15 wherein the carbon residue comprises a petroleumproduct.
 17. The method of claim 15 wherein the second amount of cokeprecursor material derived from lignin comprises by weight at least 0.01percent to less than 50 percent of a total amount of precursor materialused to make the coke.
 18. A monolithic graphite article having a volumeof at least 1 cubic centimeter formed from a precursor including atleast five percent by weight of lignin based coke and d₀₀₂ spacing ofmore than 3.36 angstroms and less 3.44.
 19. The graphite article ofclaim 18, wherein the graphite article exhibits a 2θ angle between 26°and 27°.
 20. The graphite article of claim 18, wherein the graphitearticle has a CTE of at least 0.26 ppm/° C.